i agree that your son has lied.
if he really felt she was too good for him and was doing her a favour, his heart would be breaking now to hear how she is and that theres a baby...the fact that hes being cold and appears not to care less shows he just fell out of love with her - probably married too soon - or met someone else and just needed a way out.
i also agree she needs a doc...shes had a shock...her hormones are all over the place, and she needs some medical help to get her to a better place,
its pointless trying to get your son to go back, and also bad for her to think he might go back (although for now that belief may help until time has passed and shes stronger)
sad to say its better that she begins to feel anger towards him, at least for now, as itll help break the 'spell' he has over her an help her move on...